Canthigaster compressa or C. solandri

Canthigaster compressa might appear rare on Zootierliste but is a common species in the trade. The species has very thin, horizontal lines all over its body, which is not the case for your animal here. Canthigaster solandri belongs to a species complex, almost always incorrectly identified throughout aquariums worldwide. The real solandri, also present in captivity, is a typical spot-only fish. The animal in your photo has lines on the upper part of the body. Also commonly confused is Canthigaster papua, a bigger and more robust species that is easily distinguished by having an orange mouth. The species you have here is perhaps the most common one of all, which is also of questionable identity. It requires scientific confirmation, but there is a very big chance that the tobies looking like the one here belongs to the species Canthigaster petersii. If you want to play it completely safe, it is best to write them down as Canthigaster cf. petersii, suggesting that the validity cannot be 100% sure but most likely belongs to this race.

Yeah it didn't seem compressa to me. I'll just write it down as Canthigaster sp.

@ralph It is not compressa, indeed. No need to keep it as Canthigaster sp. either though, you can safely assume that Canthigaster petersii is correct.